Anyway, I paste here the same info with a quick and dirty translation:

Instructions for using C64 disk images on the SD card:

You must use a SD/SDHC card exclusively to use with this core, since it will not use a standard format. It works concatenating .D64 disk images in a single file, and dump it to the SD in RAW, in blocks of 256K (the .D64 are 170Kb, so we use a dummy, which is included in the pack).

You can already find a prepared image to wirte to the SD (with some examples, G'n'G, command, cybernoid, some demos ..), in a file "DISKRAWC64.BIN" and a .bat + dummy script to prepare your image, here (External link not linked to the forum or the web. We are not responsible):

- First of all: the procedure will destroy everything you have on the SD card.- Using the preferred program (DD, HDD Raw Copy tool or whatever you want), write the file DISKSRAWC64.BIN to the SD card.

If you prefer you can make your own image, with .D64 disk images that you have. Simply concatenating them with a copy / b in a single file (adding a dummy in between to get 256K per image). Included is a dummy .bin and a .bat (create_C64_ALL_D64.bat) that fetches all .D64 from the current directory and generates a DISKSRAWC64.BIN file (it will boo whatever it is) ready to write. Be careful with the names of .d64 files, if they have some punctuation characters like!, &, Etc, you may not do it well. Better rename them.

And about the tape loading, yes, it will load tapes via audio from the EAR jack connector the ZX-Uno has, as with the Spectrum core. Take care of the polarity of the signal. The spectrum handles that automatically, but not the C64. If the tapes do not load the header, check inverting the polarity (key "+" of the numeric pad.